Been there and done that, tried to rebarrel a SA Rem 700 to 221FB. The action was factory barreled for 223. The 221 rebarreled gun would not feed at all, and it dropped empty or loaded cases on the follower instead of ejecting them. The gunsmith replaced the Remington extractor with a Sako extractor, but that showed no improvement. I had the 221 chambered barrel rechambered to 223. It functioned fine as a 223.
Sako A1 actions work fine for the 221 FB cartridge. I have one in 221 and 20 Vartarg, both feed and eject just fine. The problem with Sako actions is that they’re scarce and expensive these days. And if you don’t have a stock, there’s very few makers of them.
